| Title |
Thermal Properties and Durability of a Rare-Earth-Doped YSZ Bilayer Coating System |
| Authors |
이계원(GyeWon Lee) ; 최용석(YongSeok Choi) ; 전학범(HakBeom Jeon) ; 김종일(JongIl Kim) ; 이창우(ChangWoo Lee) ; 편장혁(JangHyeok Pyeon) ; 양승철(SeungCheol Yang) |
| DOI |
https://doi.org/10.3365/KJMM.2025.63.10.853 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Thermal barrier coating (TBC); Thermal conductivity; Bilayer coating; Thermal cycling durability |
| Abstract |
To protect gas turbine hot section components from operating temperatures exceeding 1100 oC,
thermal barrier coating systems are used. Although yttria-stabilized zirconia (YSZ) is commercially used
as a thermal barrier coating material, it is destabilized by phase transformations when exposed to
extremely high-temperature operating environments (>1200 oC). In efforts to resolve this critical issue,
Gd2O3- and Yb2O3-doped YSZ species have been developed as candidate alternative materials.
Compared with conventional YSZ, however, GdYb-YSZ exhibits reduced thermal cycling resistance
performance under 1400 oC thermal cycling test conditions. To overcome this drawback, a bilayer TBC
structure was designed and prepared using conventional YSZ and rare-earth-oxide-modified GdYb-YSZ
in the current study. The thermal conductivity and high-temperature thermal cycling durability were
subsequently evaluated for bilayer coatings with various thickness ratios of YSZ (bottom layer) and
GdYb-YSZ (top layer). Additionally, YSZ derivatives respectively doped with Sc2O3, Gd2O3, Dy2O3, and
TiO2 (developed in our previous research) were prepared in both single-layer and bilayer structures and
the thermal conductivity and thermal cycling durability were compared for both structures. All bilayerstructured
TBC samples respectively exhibited lower thermal conductivity than the single-layer YSZ
baseline value of 1.1 W/(m·K). Moreover, in high-temperature thermal cycling durability assessments, the
bilayer structures exhibited equivalent or superior durability compared with the single-layer YSZ coating.
These findings highlight the potential of these materials for use as advanced TBC materials in gas
turbines. |